Cutting tool



Patented Dec. 28, 1948 UNITED STATES PATENT oFF-rcs Herbert L. Trautmann, Los. Angeles,4 Calif., as-

signox. to. Cherry Rivet Company,V lios Angeles', Calif., .a corporation of California ApplicationtDecemher 14, 19451SerialiNo.- G35-,Q65

lirClaims. I.

This invention relates to: cutting tools and has particular reference toA a rivet stem. trimmer which finds particular utility: when; employed'` to cut. oi the protruding rivety stemremaningater the setting of certain types-.of blindrivets;

In certain` types of construction-and particularlyv in the construction. oflaircrafttthere is. occasion to use a type oi rivet' which. is. popularly known asa blind rivet?` the namer being*` derived froml the fact that the rivet may; beinstalled in those locations Where; accessi may be; had to..V only one side of the Work, thuspreventingtheusezof conventional rivets; with riveting: hammers: and buckingq-bars- One Wide-ly used.' type, of.Y blind rivet'A comprises; a: headed tubularA rivet. which; is insertableiinto'- the rivet receivingzholesfand which includes a stem member.. The: stem member is drawn. outwardly during the; setting; operation andi-n. so; doing formsa rivethead onthe opposite sideV ofthe Worn pieces.. Thesetting apparatus used; ordinarily operates to,- break. the rivet stem in tension when the: setting operation iscomplete. This; leaves a protruding stern which must.. later be cut off fluslrwith the; head oitherriveeiand, in the case of. aircraft constructions,y must be carefully smoothedfand contoured .to reduceteA a minimumfthe projection of the rivet assembly vbeyondthezskin of the-aircraft. t

Prior. to my inventionfthis; cutting; and.I trimming operation wasperformed in alaborious; and time-consuming manner through thefuse'cf hand cutter-3 hack-saws,A files; and. likefhand tools. As a-.result considerable time was lost. in .completing installations employing blind.- rivets11V andy an undesirable lacie. of., uniformity vin thenishedproduct. characterized the installation.4v Furthermore, attempts, to use rotating.- cuttersl havebeenunsuccessi-.ul becauseofe. thee tendency toffrctatethe; rivet stem; Within the rivet body.y Witlzr a. consequent loosening of theriveti I-t is therefore.- an.- object of. mv inver-itionr to provide a cutting tool-.partieularly'adapted tofthe cutting. ofv the. protruding stems of. blind... rivets andt which.. overcomes, the, above noted.` disadvantages by. rapidly. cutting-.the stemandat the. same timef smoothing. and. humishing; thev remaining portion.. to a.. smooth.. surface, congruent with the contouroithefrivethead.

ltjiisalso an oblectoimy. invention tor provide a. tooLof-y the-character setiortnin thepreceding paragraph Whiohmav he, held. and operatedin onahandr.

Itis an. addtcnaloblecin of;V my inventiQn..to provide.. a tool. of.' the-f character setaforthtinthe preceding paragraph'whiehtineludesa meansiorl 22 eiectingirom the tool the cut oi portion of' the rivet stem.

ItA is4 astill. further object. oilV my invention to provide a tool of theicharacter referredto hereinbefore, which. includes. a. means. flor. manually controlling. the rate. atlwhich. the rivet s-temi'scut.`

Other objectsand advantages. of my invention will. be. apparent. from a study of the. io'llowing specifications; read in. connection` with the. ace eon'ipanying.v drawings, wherein;

Fig, lisa verticallsectionalview througha cutting tool. comprising Athe preferred. embodiment of. my invention and showing the normal, positiens occupied by theparts prior to the initiation ofjacuttingoperation;

Fig, 2 is a View. siinilarto Eig. 1.- butill'ustrat.- ing` they relativepositions. of. the. parts at the end of a cuttingh operation, and illustrating the manner. in which `the cutting of. the. rivet. stem is effected;

Fig. 3.is.a.Y perspective view of thev stem'engag.- ing mandrelportion. of the-mechanism illustrated inFig. 1.;

Fig. 4. is. an end. view taken in, the direction represented. by the line IV-LV in Fig. 1v and showing; the planetary motion of. the cutting. oriflee .andstem engaging mandrel relative to each other;..

Fig. 5 is.. a fragmentary sectonalview illustrating the operation of. a\stem,ejecting means.;l and Fig. Gis a cross. 'sectionalview taken' substantially. along the. line VI-VI of'Fig, 2.

Referring. no WI to the. drawings, I have illustrated.in1.ig. 1 the preferred embodiment. of my invention as .comprising a stem trimmer for severingthe protruding rivet stem remaining after the setting of certain. typesv of blind; rivets. The apparatus, WhichY is. illustrated in 1 includes ahousing, I to whichissecured ai handle. member L permitting the` deviceto .be held. in thehand of an. operator.. The-forward end. of. the housing. i may be threaded asindicatedY at 3f to receive a can memher Ll..` The cap.. member 4 includes. a forwardly projecting..cylindricalportion 5Y of reduced.r diameter to. thereby provide. a. radially.I extendingr flange portioni.

The, interior ofY the housing l ishoredlas, shown atl 'l andI inV the forward portion of. the. housing l this. here is increased', in. diameter, asr shovfnvatY 8, to,receive. aroller. orneedle bearingH.. Endwise movement of the needle bearing 9`in one direction Withrespect tnsthehonsing.A l. is .preventedby a shoulder. l0'flilrrriedby theenlarg-ed .bore portion, andi. inthe. other. directionby a. Washer. member Il Whicnslideszwithinsthe enlarged horeportion r 8 and is held in place by means of the cap 4. The Washer I I and the cap 4 are both internally bored and the edges of the bores are chamfered as shown at I2 and I3 to dene a quasi-spherical socket for receiving a spherical ball portion I5 formed upon a stem-engaging mandrel member I6. The l ball and socket joint thus formed serves to hold the stem engaging mandrel I6 within the housing i against translatory motion while permitting limited universal motion thereof. The mandrel member I6 includes a portion II extending forl wardly from the ball I5 to a point near the forl bearing member I9 is 'slidably received within a bore 20 formed in the driving member 2|, the bore 2|) being extended at `an acute angle to the axis of the driving member 2 I. The driving member 2|' is rotatable and slidable within the bore 'I and withinv the needle bearing 9, and is arranged to be rotated by a shaft 22 which is formed integrallywith the driving member 2| or suitably attached thereto, and which extends rearwardly through an open rear end 23 of the housing I. The driving member 22 may be rotated by any suitable means, as by hand or through a flexible l wardmost end of the cylindrical cap extension i 5. It also includes a rearwardly extending p0r-` 1 tion I8 upon which is mounted a bearing member I9. The bearing member I9 ispreferably a ball or roller bearing characterized by including an outer race member, the external surface of which constitutes a segment of-.a spherical surface. The

shaft extension 55 to a suitable power means BID shown in Fig. l. If desired a power driving means such as an electric or pneumatic motor 55 (Fig. 2) may be mounted on the apparatus and in .connection with the drive shaft 22.

The shaft 22 is journaled for rotation by means l of an aft bearing 24 which is supported in a sliding collar 25 positioned within the bore I. Rear- Ward movement of the sliding collar 25 may be`r 'limited to the position shown in Fig. 1 by means of a snap ring 29 placed within the aft end of the bore l'. It will be appreciated that lsliding movement of the collar 25 to the left,` as viewed in Fig.

` 1, will slide the driving member 2| to the left to a position such as is shown in Fig. 2. In such position the roller or needle bearing 9 provides the principal means which mounts the driving member 2| forrotationwithin the housing I.

'I'he above described sliding movement of the collar 25 is effected by means of a hand-grip member 2I .which is pivoted to the handle 2 as by means of a pivot pin 28. A suitable` spring such as .that shown at 29 normally urges the handgrip member 2l to the position shown in Fig. 1. As is illustrated in Fig. 6, the hand-grip member I 21 is bifurcated to provide Va pair of upstanding arms 39 and 3| which extend upwardly along opposite sides of the housing I. to a point somewhat above the horizontal diameter thereof. The u'pstanding portions 39 and 3| are vertically slotted, as shown at 32 in Fig. 2, to receive drive pins 33 and 34 mounted upon the sliding lcollar 25 and passed through longitudinally extending I slots 35 formed in the housing I. It will be seen that an operator of the tool may grip the hand- 1 grip member 21 to move the same from the posiwhen the mechanism is in its normal or initial position as shown in Fig. 1. Accordingly, when the driving member 2| is moved forwardly to the position shown in Fig. 2 the inclination of the bore 20 Will shift the center of the bearing member I9 to a point to one side of the axis of rotationvof thedriving member l2| so that upon rotation of the driving member the bearing memn ber I9 Will be moved through a circle centered on the axis of rotation of the driving member. It will be seen that the radius of this circle is a function of the distance through which the driving member 2| is moved from the initial position shown in Fig. A1.

The outermost end of the cylindrical cap extension 5 may be threaded as shown at 35 to receivea cap member 3'I used to clamp against the end of the extension 5 an orifice dening plate 38. The orifice dening plate 33 has formed therein an orifice 39 for receiving a rivet stem, the orifice 39 being sharpened as indicated at 40. The mandrel member I6 is provided with'an internal stem receiving bore 4| within which is slidably mounted a spring pressed ejector member 42. Between the ejector 42k and the bottom of the bore 4I there is placeda compression spring 43. The spring 43 is preferably tapered as shown so that the innermostl end'44 thereof may frictionally engage the walls of the bore 4I to retain the spring therein. The ejector 42 is preferably suitably secured as by soldering or brazing to the outer end of the spring 43. The operation of the tool may be seen by having reference to Fig. 2 wherein I have shown in fragmentary section two plates 45 and 46 as being secured to each other by a blind rivet. The blind rivet includes a tubular rivet body 47 which carries an outer head .48. Within the body 4'I there is placed a stem'49 having an enlargement 50 on an inner end thereof which operates to are or head the inner end of the rivet body as .shown at 5|.- f At the completion of the rivet setting operation the stem 49 extends a considerable Idistance beyond the plate 45, including a stem portion 52 which in Fig. 2 is shown as being received Within the bore 4I and already severed `from the portion 49. remaining in the rivet.k It

will be understood that this is a result of the operation of the tool and-that prior to the operation of the tool the portion 52-is an integral part of the stem 49.

Y In accordance with -my invention the stem portion 52 is severed from the remainder 49 by first Amotion`-vvvith respect to the orice 39.l Since the mandrel I'fis held against movement by its engagementl with the protruding stem portion 52 it will be seen that the entire too1,'including the housing I, the cap extension 5 and the orifice 39, will becausedto move with respect to the mandrel I6 and with respect to the rivet stem portion 5.2. It will be appreciated that by virtue of the mechanism hereinbefore described the motion thus imparted to the orifice 39 with respect to the rivet stem 52 will bea planetary motion in nemen! .which A,the-orifice Z39 :undergoes 'no rotation .about -its-.owncenter- The centeruof the .orifice '3911s thus .caused to .describe a circular motioniabout r.the iaxis .of vthe mandrel .receiving bore 1L 'The `radius -of ithis fcircle iis initially :zero when the parts .are in "the position shown in Fig. 1,':and is increased .gradually by :movement of fthe handgrip member 2LT yuntil a maximum radius is reached when the .parts are disposed in theposition shown -in 'Fig...\2. The mechanism i is @so lpro-- portioned as l-to cause fthisradius to'ibe somewhat .greater :thanjthe `rad-ius of thestem rrp'ortion lil-iso that ythe cutting Iedge 39 in progressing around vthe .stem portion V-52 will lbe -moved -nearer and nearer the center thereof `to finally completely sever the stem portion )52 as is show-n vinig '2. Since the .oriiice plate -138 fdoes not `rotate about itslovvn axis -it lis slid over the cut surface of the stem portion 52 during vthe cutting operation so as to smoothand lburnish the cut surface. By employing -a lsharpened edge 10 -of the character -shovvn'inliigs 1 and 2 the-contour of the "stcm remaining is caused to conform very closely to the eontourof the rivet headl48.

4At the Aconclusion of the .cutting operation the `the -spring pressed ejector member Al2 'to eject the :severed rivet stem portion'52 in the manner illustrated 4in Fig. 5.

From the foregoing it Will be observedrthat'I have provided a cutting toolwhich is particularly adapted to the severing of blind rivet stems, and which is so arranged as to permit it being held and operated one hand. Thek mechanism `de-V scribed includes a means forcausing a sharpedged orifice to movewith a planetary motion about the rivet stem'to be cut, and means is provided for adjusting the radius of this planetary motion so that the cutting of the rivet stemmay be eiected at any desired and controlledrate.

l AIt `Will be lnoted that the orice plate which denes the cutting oriiice does not rotate about its own center as the cutting proceeds. This avoids the difculty characterizing some former types of tools in that the rivet stem Was rotated with a consequent loosening of the rivet stem within the rivet body and a corresponding reduction in the strength and tightness of the riveted joint.

Attention is directed particularly to the provision of the ejecting mechanism which permits the severed portion to be automatically ejected from the tool by merely restoring the tool parts to their initial positions as in preparation for the severing of another rivet stem.

While I have shown and described the preferred embodiment of my invention, I do not desire to be limited to any of the details of construction shoWn or described herein,

I claim:

l. In a cutter for severing the protruding stem of a blind rivet, the combination of: a member having an orifice for receiving said stem and having sharpened edges; and a mechanism that displaces said member about said stem with a planetary motion with respect to said stem whereby said motion causes said sharpened edges to cut into said stem and sever said stem.

2. In a cutter for severing the protruding stem saidstem and imparting'to'said membera planetary ymotion with v.respect to said stem; Iand a 4support for holding said `orifice member against rotation about the center of said orice.

3. In a vcut-ter fors'evering the protruding stem vof ya A4blind rivet,.the combination of: a memlber'haa'f'ing -an ordi-ice for receiving said stem and "having sharpened edges;l a drive unit lengaging V-saii-d :stem-.and imparting tosaidmemberaplan'etary motion' with respect to said stem `whereby the center of said forice is moved around-a circle centeredon said stem; and a vmovable element associated with said drive unit for varying the Vradius-oi said circle during said motion.

4. In a'cutterfor severing the protruding stem of 4a `blind rivet, the combin'ationof: a member H-ha-ving yan orifice for -receiving said stem `and having `sharpened edges; mandrel means -for `engaging said stem; and a drive unit for `imparting to said "orifice vmember a plantary motion yabout said `mandrelwhereby the center of said orice is moved around a circle centered onfsaid stem.

5. In 'a'cutter forsevering the protruding stem of a blind rivet, the combination of: -a member having an oriice for receiving said stem and having sharpened edges; mandrel means for en- 'gafging said stem; a drive unit engaging said stem and imparting to said member a planetary vI notionabout said mandrel whereby the 'center ofsaid orince is lmoved around a circle centered 'on said stem; and a support for holding said oriiice member against rotation about the center of said orice.

6. 'In a cutter for severing the protruding stem of a `blind rivet, the combination of a member y'having an orice for receiving said stem and said yorifice hav-ing sharpened edges; mandrel means for engaging said stem; a drive unit for imparting to said orce member a planetary motion about said mandrel whereby the center `of saidoriiice is moved around al circle centered on 'said stem; and a movable element associated 'with said drive runit for varying the radius of said circle during said motion. i 7'. In a cutter for severing the protrudingl stem of 'a blind rivet, the combination of: means dening an orince for receiving said stem and having sharpened edges; mandrel means having a bore therein for receiving said stem; means for imparting to said orice dening means a planetary motion about said mandrel whereby the Center of said orifice is moved around a circle centered on said stem; means for varying the radius of said circle during said motion; and ejector means in said bore for ejecting therefrom the stem severed by said motion of said orifice defining means.

8. In a cutter for severing the protruding stem of a blind rivet, the combination of: a member having an orifice for receiving said stem and having sharpened edges; a drive unit for imparting to said orifice member a plantary motion With respect to said stem; and an ejector for ejecting from said orice the stem severed by said motion of said orifice.

9. In a cutter for severing the protruding stem of a blind rivet, the combination of: a housing; a mandrel in said housing having a stem receiving bore formed at one end thereof; mounting means in said housing for holding said mandrel against translatory motion While permitting universal pivotal movement thereof; drive means in 7 said housing engaging said mandrel for imparting to said mandrel a planetary motion of said one end relative to said housing; and means on said housing defining a sharp-edged orifice adjacent said end whereby the center of said orifice is moved -in a circle about a stem received in said bore.

10. In a cutter for severing the protruding stem of a blind rivet, the combination of: a housing; a

mandrel in said housing having a stem receiving bore formed at one end thereof; mounting means in said housing for holding said mandrel against translatory motion While permitting universal pivotal movement thereof; drive means in said l housing engaging said mandrel for imparting to said mandrel a planetary motion of said one end relative to said housing; means on said housing 1 defining a sharp edged orifice adjacent said end whereby the center of said orifice is moved in a lcircle about a stem received in said bore; and 1 means coacting With said drive means for varying the radius of said circle during said motion.

11. In a cutter for severing the protruding stem of a blind rivet, the combination of: a housing; a mandrel in said housing having a stem receiving bore formed at one end thereof; a ball and socket l bearing in said housing holding said mandrel against translatory motion While permitting universal pivotal movement thereof; a drive member in said housing; means mounting said drive member for simultaneous rotation and axial sliding movement in said housing, said drive member having a longitudinally extending cylindrical bore formed therein at an acute angle to the axis of rotation of said drive member; a bearing on said mandrel received in said cylindrical bore; means for rotating said drive member,

l whereby there is imparted to said mandrel a planetary motion of said end thereof relative to said housing; means on said housing defining a against translatory motion While permitting unitnAA i8 versal pivotal movementthereo; a drive membe in said housing; means mounting said drive member for simultaneous rotation and axial sliding movement in said housing, -said drive member having a longitudinally extending cylindrical bore formed therein at an acute angle to the axis of rotation of said drive member; a bearing on said mandrel received-in said cylindrical bore; means for rotating said drive member; meanslon said 4housingdening a sharp edged orice adjacent said end; means for sliding said drive member in i said housing during'rotation thereof; and spring pressed ejector means in said stem receiving bore for ejecting' therefrom the stem severed by the planetary motion of said orifice thereabout and resulting fromr rotation of said ldrive member.

,f 13. In a stem cutter that also burnishes the cut stem, the combination of: a member having an orifice for receiving said stem, which orifice has sharpened edges; a drive unit for imparting to said orifice member a'planetary motion-With respectV to said stem; and a source of power having a driving engagement With said drive unit,- Whereby the planetary motion of the orifice member causesy the sharp edges of thel orifice to bite into the stem in a progressive manner, burnishing the surfacesas they are progressivelyrcut. p t

14. VIn a cutter for severing the protruding stem of a blind rivet, the combination of a handle; a housing mounted on said lhandle and having a portion thereof apertured and the edges of the aperture sharpened; a drive unit disposed Within said housing; a stem-gripping element driven Within a circular path Within said housing adjacent to said aperture; and a motor secured to said housing for driving said drive unit.

i f HERBERT L. TRAUTMANN. v

v REFERENCES yCITED The'following references are of 'record in the file of this patent: f

' UNITED STATES PATENTS' Number' Name Date 535,771 Richards Mar. 12, 1895 1,085,967 Brown 'Feb.-3, 1914. f 1,206,311 Dillinger j Nov. 28, .1916 

